Field of the Disclosure
The present application relates to a display device, and more particularly, to a source driver, a display device with the same and a driving method thereof which are adapted to reduce power consumption by adjusting a bias voltage applied to an output buffer of the source driver.
Description of the Related Art
A display device includes a display panel configured to display an image and drivers configured to drive the display panel. The display panel includes a plurality of data lines and a plurality of gate lines. Also, the display panel includes pixels formed in regions which are defined by the pluralities of data lines and gate lines crossing each other. The display panel can become one of a liquid crystal display panel, an organic light emitting diode display panel, an electrophoresis display panel, a plasma display panel and so on.
The drivers include a source driver and a gate driver. The source driver is used to drive the data lines on the display panel. The gate driver is used to drive the gate lines on the display panel.
The source driver includes a plurality of output buffers each configured to buffer a data voltage which is applied from a respective digital-to-analog converter. The output buffers are connected to the data lines on the display panel by ones. Also, the output buffers transfer the buffered data voltages to the respective data lines.
In this manner, the data voltages used to drive the pixels on the display panel are output through the output buffers built-in the source driver. As such, the properties of the output buffers must affect image quality of the display panel.
Recently, the display panel becomes larger size and higher definition. As such, the display panel is required to drive in a high frame frequency. Also, the source driver is configured in a multi-channel mode with several driver IC (integrated-circuit) chips. Each of the source driver IC chips can apply the data voltages to some of the data lines.
Particularly, in order to enhance the performance of the large-sized high definition display panel, the performance of the output buffer of the source driver must be enhanced. The performance of the output buffer is largely affected by a bias current which is applied to the output buffer.
FIG. 1 is a data sheet illustrating properties of an input bias current and an output voltage of an output buffer of a source driver according to the related art.
As shown in FIG. 1, the output voltage (i.e., the data voltage) output from the output buffer of the source driver depends on the bias current applied to the output buffer.
As examples of the bias voltage, a first bias current Ibias1 and a second bias current Ibias2 can be selectively applied to the output buffer of the source driver. In this case, it can be confirmed that the output voltage of the output buffer is output (or transferred) almost no delay when the first bias current Ibias1 a relatively larger value compared to the second bias current Ibias2 is applied, as shown in FIG. 1.
On the contrary, when the second bias current Ibias2 being smaller than the first bias current Ibias1 is applied, rising and falling edges of the output voltage output from the output buffer are delayed as shown in FIG. 1.
Although a large-sized display panel is driven in a high frame frequency, the source driver using a large bias current Ibias can output an output voltage without any delay. As such, the large bias current applied to the output buffer of the source driver can prevent deterioration of image quality of the display panel.
However, as the bias current applied to the output buffer of the source driver increases, power consumption must become larger.
Also, since the plurality of output buffers is disposed in the source driver, the large bias current Ibias applied to each of the output buffers must generate heat. Due to this, performances of the source driver and the display device must deteriorate.